In the past three decades refinements of surgery and radiotherapy have failed to improve the prognosis of patients harboring malignant gliomas, and even under the best of circumstances, surgery and radiotherapy seldom, if ever, achieve more than a 2 log reduction of tumor containing 10 to the 11th power cells. Now that we know the kinetic parameters of malignant gliomas and can recognize the desired pharmacological characteristics of potentially useful drugs, we should exploit this knowledge in an effort to cure tumors, first in animal models and later in man. As we comtemplate a multimodality approach to brain tumors, immunotherapy should be cautiously explored. Relatively free of systemic toxicity, immune enhancement is compatible with surgery, irradiation and chemotherapy, and may be capable of eliminating the final few logs of neoplastic stem cells. Our immediate objective is to combine individually effective agents in a carefully designed problem that will achieve maximal cell kill. Our ultimate objective is a curative therapeutic plan involving the combined use of surgery, radiotherapy, chemotherapy, and immunotherapy. In pursuing both objectives, laboratory research will provide the necessary basis for therapeutic trials in man. BIBLIOGRAPHIC REFERENCES: Barker, M., Hoshino, T., Wheeler, K.T. and Wilson, C.B. Chemotherapeutic implications of early tumor cell growth in an animal brain tumor model. J. Nat. Cancer Inst. 54:851-853, 1975. Calogero, J., Crafts, D.C., Wilson, C.B., Boldrey, E.B., Rosenberg, A. and Enot, K.J. Long-term survival of patients treated with BCNU for brain tumors. J. Neurosurg. 43:191-196, 1975.